1. Field of the Invention
The present invention relates to an ejector which is a kinetic pump for transferring a fluid by using entrainment of a high-speed jet flow of a driving fluid. The ejector is suitably used for a vapor compression refrigerant cycle (ejector cycle) where the ejector is used as a pumping unit for circulating refrigerant (JIS Z 8126 2.1.2.3).
2. Description of Related Art
In an ejector cycle described in JP-A-10-205898, high-pressure refrigerant is decompressed and expanded in a nozzle of an ejector, and a low-pressure refrigerant in the evaporator is circulated by the pumping function of the nozzle of the ejector. Further, in the ejector cycle, a pressure of refrigerant to be sucked into a compressor is increased by converting expansion energy of refrigerant to pressure energy thereof, so that consumption power of the compressor is reduced.
In this ejector cycle, as an energy converting efficiency in the ejector, that is, an ejector efficiency becomes lower, the pressure of refrigerant to be sucked to the compressor cannot be sufficiently increased. In this case, the consumption power of the compressor is not sufficiently reduced, and a necessary amount of refrigerant may be not circulated to the evaporator.
Further, in the ejector cycle described in JP-A-10-205898, a part of refrigerant sucked from the evaporator through a suction port of the ejector flows toward a refrigerant inlet side of the nozzle, opposite to a refrigerant outlet side of the nozzle, and is turned by 108° due to collision with a wall, so as to flow toward the refrigerant outlet side. Thus, the refrigerant sucked from the suction port of the ejector has a large pressure loss. As a result, it is difficult to effectively increase the ejector efficiency.